The present invention relates to an aluminium section member assembly with a thermal bridge gap for window and door frames.
Prior aluminium section members, including a thermal bridge gap, for making window and door frames conventionally comprise an outer section member made of extruded aluminium and an inner section member also made of extruded aluminium, which are rigidly coupled to one another by coupling strips or small bars made of a thermally insulating synthetic material, usually a polyamide material. These prior strips operate to provide a mechanical coupling between the two extruded aluminium section members, while interrupting the thermal conductibility between the two metal section members.
The coupling between the outer section member and inner section member, provided by using the above two strips, generates, between the two metal section members, a chamber defined by said two strips and by that region of the two metal section members which is arranged between said strips.
Inside the mentioned chamber convective hot and cold air flows can be generated, depending on the time or seasons, which practically provide a thermal transmission between the two metal section members.
The above mentioned thermal transmission, even if is comparatively small, causes a some amount of heat to flow between the outer metal section member and inner metal section member.
In order to solve this problem, a prior method provides to fill-in into said inner chamber, as the outer section member and inner section member are coupled, a thermally insulating material, of any desired suitable natures, such as, for example, polyurethane foamed materials, cast resin materials, plastic material films and the like.
This method allows to eliminate, or reduce, the thermal transmission between the metal section members: however, it requires specifically designed section members, which must be provided with different characteristics, both from a technical standpoint and from an economical standpoint and actually, prior section members for solving the above mentioned problems have been found to be greatly expensive, since they require comparatively long making steps.